Diazo type photosensitive sheet developing device

ABSTRACT

A device comprising a cylindrical member having magnet means mounted in its interior and a guide plate disposed along an outer peripheral surface of the cylindrical member for a part of its circumferential extent and spaced apart from it. A developing agent comprising iron in powder form moist with a developing liquid, e.g., an organic amine, is filled in a gap defined between the guide plate and the cylindrical member to provide a magnetic brush which is rotated while exposed binary system photosensitive sheets of the diazo type are introduced into the gap to be developed by means of the magnetic brush cooperating with the guide plate.

United States Patent [191 Takahashi 1541 DIAZO TYPE PHOTOSENSITIVE SHEETDEVELOPING DEVICE [75] Inventor: Yasuhiro Takahashi, Tokyo, Japan [73]Assignee: Ricoh Co., Ltd., Tokyo, Japan [22] Filed: Feb. l1, 1972 [2l]Appl. No.: 225,437

[30] Foreign Application Priority Data [451 Oct. 8, 1974 PrimaryExaminer-Robert R. Mackey Assistant Examiner-Leo Mllstein Attorney,Agent, or Firm-Cooper, Dunham, Clark, Griffin & Moran [5 7 ABSTRACT Adevice comprising a cylindrical member having magnet means mounted in'tsinterior and a guide plate disposed along an outer peripheral surface ofthe cylindrical member for a part of its circumferential extent andspaced apart from it. A developing agent comprising iron in powder formmoist with a developing liquid, e.g., an organic amine, is tilled in agap dened between the guide plate and the cylindrical member to providea magnetic brush which is rotated while exposed binary systemphotosensitive sheets of the diazo type are introduced into the gap tobe developed by means of the magnetic brush cooperating with the guideplate.

9 Claims, l Drawing Figure DIAZ() TYPE PHOTOSENSITIVE SHEET DEVELOPINGDEVICE BACKGROUND OF THE INVENTION DESCRIPTION OF A PREFERRED EMBODIMENTThe photosensitive sheets of the diazo type used in This inventionrelates to a developing device for b- 5 this invention are of the knowntype which has a photonary system photosensitive sheets of the diazotype wherein a developing agent comprising iron in powder form moistwith an alkaline developing liquid is used for effecting developing bymeans of a magnetic brush.

The use of a developing agent comprising minute powder moist with analkaline developing liquid, such for example as an organic amine, fordeveloping exposed binary system photosensitive sheets of the diazo typeoffers many advantages. The duplicates made by using this developingagent are free from odor which tends to render the duplicates made byusing ammonia rather objectionable. The developed photosensitive sheetsare not discharged from the copying machine in wet condition which isthe case when the photosensitive sheets are developed with a liquiddeveloping agent. The use of the developing agent described abovepermits duplicates of good tone and contrast to be made and provided indry condition.

SUMMARY OF THE INVENTION An object of this invention is to provide anovel diazo type photosensitive sheet developing device wherein adeveloping agent comprising a ferromagnetic material in minute powderform moist with an alkaline developing liquid is used to provide amagnetic brush on the outer peripheral surface of a cylindrical memberby attracting such material to the cylindrical member by magnet meansmounted in the interior of the cylindrical member, so that thedeveloping liquid can be supplied by means of such magnetic brush tophotosensitive sheets delivered to this developing device after beingexposed to an optical image of an original.

Another object of the invention is to provide a diazo typephotosensitive sheet developing device which facilitates the movement ofphotosensitive sheets through the device and permits a number ofdiscrete exposed photosensitive sheets to be developed successively andcontinuously in such manner that not much powder adheres to the surfaceof each duplicate.

This device offers many advantages. The provision of the magnetic brushon the outer peripheral surface of the cylindrical member permits asmany exposed photosensitive sheets as desired to be developedsuccessively and continuously. The movement of the photosensitive sheetsthrough the developing device is facilitated, and little powder adheresto the surface of each developed sheet. Since the magnet means mountingshaft disposed in the cylindrical member can be removed therefrom, thebatch of developing agent disposed on the outer peripheral surface ofthe cylindrical member can be replaced by a new batch. Last not butleast important is the fact that since various parts of the developingdevice are disposed conveniently about the cylindrical member, it ispossible to obtain a compact overall size in a developing device.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a sectional view of thediazo type photosensitive sheet developing device comprising oneembodiment of this invention.

sensitive layer consisting of a mixture of a diazonium salt and itscoupler, and a photosensitive layer supporter or base which may be paperor a sheet of a synthetic resinous material. In effecting developing inthis invention, an alkaline developing liquid, such for example asmonoethanol amine or other organic amine is employed. A ferrogmagneticmaterial in minute powder form, such for example, example iron, cobalt,nickel or an alloy thereof, an alloy of one of such metals with othersuitable metal, or an alloy comprising manganese and copper, is used asa carrier for the alkaline developing liquid.

On the other hand, a cylindrical member used in this device for housingmagnet means therein is preferably made of a non-magnetic material, suchfor example as aluminum, an aluminum alloy or a synthetic resinousmaterial.

One embodiment of this invention will now be described with reference tothe accompanying drawing.

In the drawing, a developing agent l comprising a ferromagnetic materialin minute powder form moist with an alkaline developing liquid iscontained in a vessel 2 in which is rotatably mounted a cylindricalmember 3 of relatively large diameter made of a nonmagnetic material. Ashaft 4 mounted axially in cylindrical member 3 is hexagonal incross-section, and a magnet supporter 5 is attached to every other sideof shaft 5. Diverging two arms of each magnet supporter 5 each carrythereon a permanent magnet 6 mounted with a north pole being disposedadjacent an inner peripheral surface of cylindrical member 3. It is tobe understood that this invention is not limited to the method ofmounting the magnet means described herein and that the magnet means maybe mounted in any other suitable manner. The positions of the poles ofeach permanent magnet may be conveniently changed, and electromagnetsmay be used in place of permanent magnets as the magnetic means.

Cylindrical member 3 and shaft 4 are driven by suitable motors 3a and 4ato rotate in the direction of an arrow a, with magnets 6 rotating aboutthe axis of shaft 4. Each magnet 6 attracts developing agent l to anouter peripheral surface of cylindrical member 3 when it draws nearcontainer 2, so that a magnetic brush 7 is formed along the lines ofmagnetic force of the magnet means.

A photosensitive sheet guide plate 8 is mounted above a left upper halfportion of cylindrical member 3 as shown in the FIGURE to be disposedalong a portion of the outer peripheral surface thereof. Defined betweenguide plate 8 and the outer peripheral surface of cylindrical member 3is a gap which is of dimension such that magnetic brush 7 disposed inthe gap is maintained in engagement with an inner surface of guide plate8.

A pair of rollers 9 for introducing photosensitive sheets into the gapis mounted at an entrance to the gap or at a lower end of guide plate 8in a left lower portion of the FIGURE. Binary system photosensitivesheets of the diazo type are moved in the direction of an arrow b anddelivered to the pair of rollers 9 by another guide plate l0 after beingexposed to an optical image of an original. Each photosensitive sheet isgripped by the pair of rollers 9 and introduced into the gap betweenguide plate 8 and cylindrical member 3 with its photosensitive layerfacing the outer peripheral surface of cylindrical member 3.

The magnetic brush 7 on cylindrical member 3 is adapted to rotate at arate greater than the rate at which each photosensitive sheet moves inthe gap between guide plate 8 and cylindrical member 3. As a result, themagnetic brush rubs against the photosensitive layer ofeachphotosensitive sheet which receives a supply ofthe alkaline developingliquid so that the exposed photosensitive sheet is developed.

Cylindrical member 3 and the shaft l supporting magnets 6 may rotate asa unit or may rotate separately at different rates of revolutions.Cylindrical member 3 may be firmly fixed without rotating if desired.However, cylindrical member 3 is preferably rotated so as to permit eachphotosensitive sheet to move through the gap between guide plate 8 andcylindrical member 3 smoothly. The inner surface of guide plate 8 ispreferably finished to provide a smooth planar surface. The smooth innersurface of guide plate 8 cooperates with the rotating magnetic brush topermit photosensitive sheets of minumum thickness to move through thegap between guide plate 8 and cylindrical member 3 without trouble` Athin sheet 2a as of polyester is attached to an upper edge of vessel 2disposed on the guide plate side and mounted along the path of movementof photosensitive sheets so as to keep the developing agent from fallingdownwardly between the upper edge of vessel 2 and the inner surface ofguide plate 8.

A pair of rollers lll and l2 maintained in pressing engagement againsteach other is mounted at an exit of the gap or at an upper end of guideplate 8. A combined photosensitive sheet stripper and guide l consistingof a number of sheets of a synthetic resinous material is supported byupper and lower support shafts 13 and 14 and disposed adjacent oneroller l2. Combined stripper and guide l5 has a plurality of pawls 15a(only one is visible in the drawing) maintained lightly in pressingengagement with the outer peripheral surface of cylindrical member 3, sothat they can engage the leading end of each photosensitive sheet movingtoward the exit of the gap after being developed to strip thephotosensitive sheet off the cylindrical surface and direct the sametoward two rollers lll and l2.

The developed photosensitive sheet gripped by two rollers lll and l2 isdelivered to a pair of cleaning cylinders 16 and l7 rotating in adirection opposite to the direction of movement of the developedphotosensitive sheet. Permanent magnets t8 and E9 are housed in cleaningcylinders ll6 and ll7 respectively, so that the minute powder of thedeveloping agent adhered to the surface of the developed photosensitivesheet can be removed therefrom by being attracted to outerperipheralsurfaces of two cleaning cylinders 16 and 17.

Scrape-off plates 20 and 2li are mounted such that their forward endsare maintained in pressing engagement with outer peripheral surfaces ofcleaning cylinders 16 and i7 respectively to scrape off the powderattached to the developed photosensitive sheet. Scrape-ol plates 20 and2l are preferably made of metal or other resilient material and securedto fixed shafts 22 and 23 at their bases.

What l claim is:

l. A diazo type photosensitive sheet developing device comprising avessel for a developing agent including powdered magnetic materialmoistened with developing fluid, a cylindrical member mounted forrotation about its axis and partly immersed in said vessel to contactthe developing agent contained therein, magnet means mounted for coaxialrotation inside the cylindrical member for attracting developing agentto form a brush of developing agent adhering magnetically to the outerperiphery of the cylindrical member, a photosensitive sheet guide platemounted along a segment of the outer periphery ofthe cylindrical memberand spaced apart therefrom to form a gap, said magnet means comprising aplurality of magnets circumferentially spaced from each other bysufficient distances to form said brush in the shape of a plurality ofridges of powdered magnetic material moistened with developing fluid,each ridge facing the guide plate, extending axially and having a peakcontacting said guide plate, each pair of adjacent peaks that contactthe guide plate being separated by a valley having a bottom extendingaway from the guide plate by a substantial distance as compared to theplate -tocylindrical member distance, means for rotating the cylindricalmember and the magnet means at different relative speeds, and means forintroducing an exposed diazo type photosensitive sheet in the gapbetween the cylindrical member and the photosensitive sheet guide platefor conveying the sheet along the guide plate at a lower speed than thespeed of said brush along the guide plate.

2. A developing device as in claim l wherein the gap between the outerperiphery of the cylindrical member and the photosensitive sheet guideplate is less than the general thickness of the magnetic brush formed ofde` veloping agent adhering to the outer surface of the cylindricalmember.

3. A developing device as in claim ll including means for extractingphotosensitive sheets introduced into the gap between the cylindricalmember and the photosensitive sheet guide plate and means for removingdeveloping agent adhering to the sheets extracted by said extractingmeans.

4. A developing device as in claim 3 wherein said developing agentremoving means comprises a pair of cleaning cylinders mounted parallelto and abutting each other, means for passing between said cleaningcylinders sheets extracted by said extracting means, and magnetic meansmounted in said cleaning cylinders to attract to the outer periphery ofthe cleaning cylinders developing agent adhering to the sheets passingbetween the cleaning cylinders.

5. A diazo type photosensitive sheet developing device comprising avessel for a developing agent including powdered magnetic materialmoistened with developing fluids, a cylindrical member mounted forrotation about its axis and partly immersed in said vessel to contactthe developing agent contained therein, magnet means mounted for coaxialrotation inside the cylindrical member for attracting developing agentto form a brush of developing agent adhering magnetically to the outperiphery of the cylindrical member, a photosensitive sheet guide platemounted along a segment ofthe outer periphery of the cylindrical memberand spaced apart therefrom to form a gap, means for rotating thecylindrical member and the magnet means` means for introducing anexposed diazo type photosensitive sheet in the gap between thecylindrical member and the photosensitive sheet guide plate, means forextracting photosensitive sheets introduced into the gap between thecylindrical member and the photosensitive sheet guide plate and meansfor removing developing agent adhering to the sheets extracted by theextracting means, wherein said developing agent removing means comprisea pair of cleaning cylinders mounted parallel to and abutting eachother, means for passing between said cleaning cylinders sheetsextracted by the extracting means and magnetic means mounted in thecleaning cylinders to attract to the outer periphery ot' the cleaningcylinders developing agent adhering to the sheets passing between thecleaning cylinders.

6. A developing device as in claim 5 wherein the cyber and the magnetmeans at different speeds.

1. A diazo type photosensitive sheet developing device comprising avessel for a developing agent including powdered magnetic materialmoistened with developing fluid, a cylindrical member mounted forrotation about its axis and partly immersed in said vessel to contactthe developing agent contained therein, magnet means mounted for coaxialrotation inside the cylindrical member for attracting developing agentto form a brush of developing agent adhering magnetically to the outerperiphery of the cylindrical member, a photosensitive sheet guide platemounted along a segment of the outer periphery of the cylindrical memberand spaced apart therefrom to form a gap, said Magnet means comprising aplurality of magnets circumferentially spaced from each other bysufficient distances to form said brush in the shape of a plurality ofridges of powdered magnetic material moistened with developing fluid,each ridge facing the guide plate, extending axially and having a peakcontacting said guide plate, each pair of adjacent peaks that contactthe guide plate being separated by a valley having a bottom extendingaway from the guide plate by a substantial distance as compared to theplate -to- cylindrical member distance, means for rotating thecylindrical member and the magnet means at different relative speeds,and means for introducing an exposed diazo type photosensitive sheet inthe gap between the cylindrical member and the photosensitive sheetguide plate for conveying the sheet along the guide plate at a lowerspeed than the speed of said brush along the guide plate.
 2. Adeveloping device as in claim 1 wherein the gap between the outerperiphery of the cylindrical member and the photosensitive sheet guideplate is less than the general thickness of the magnetic brush formed ofdeveloping agent adhering to the outer surface of the cylindricalmember.
 3. A developing device as in claim 1 including means forextracting photosensitive sheets introduced into the gap between thecylindrical member and the photosensitive sheet guide plate and meansfor removing developing agent adhering to the sheets extracted by saidextracting means.
 4. A developing device as in claim 3 wherein saiddeveloping agent removing means comprises a pair of cleaning cylindersmounted parallel to and abutting each other, means for passing betweensaid cleaning cylinders sheets extracted by said extracting means, andmagnetic means mounted in said cleaning cylinders to attract to theouter periphery of the cleaning cylinders developing agent adhering tothe sheets passing between the cleaning cylinders.
 5. A diazo typephotosensitive sheet developing device comprising a vessel for adeveloping agent including powdered magnetic material moistened withdeveloping fluids, a cylindrical member mounted for rotation about itsaxis and partly immersed in said vessel to contact the developing agentcontained therein, magnet means mounted for coaxial rotation inside thecylindrical member for attracting developing agent to form a brush ofdeveloping agent adhering magnetically to the out periphery of thecylindrical member, a photosensitive sheet guide plate mounted along asegment of the outer periphery of the cylindrical member and spacedapart therefrom to form a gap, means for rotating the cylindrical memberand the magnet means, means for introducing an exposed diazo typephotosensitive sheet in the gap between the cylindrical member and thephotosensitive sheet guide plate, means for extracting photosensitivesheets introduced into the gap between the cylindrical member and thephotosensitive sheet guide plate and means for removing developing agentadhering to the sheets extracted by the extracting means, wherein saiddeveloping agent removing means comprise a pair of cleaning cylindersmounted parallel to and abutting each other, means for passing betweensaid cleaning cylinders sheets extracted by the extracting means andmagnetic means mounted in the cleaning cylinders to attract to the outerperiphery of the cleaning cylinders developing agent adhering to thesheets passing between the cleaning cylinders.
 6. A developing device asin claim 5 wherein the cylindrical member and the magnet means rotate atdifferent speeds.
 7. A developing device as in claim 5 wherein thecylindrical member and the magnet means rotate at different angularspeeds.
 8. A developing device as in claim 5 wherein the means forrotating comprise a first rotating means for rotating the cylindricalmember about its axis at a selected first speed and second rotatingmeans for rotating the magnet means about the same axis.
 9. A developingdevice as in claim 8 wheRein said first and second rotating means rotatethe cylindrical member and the magnet means at different speeds.